MPs are due to vote on legislation which paves the way for a radical overhaul of England's school system.
The Academies Bill will allow all schools to opt out of local council control, some as soon as September.
Ministers say these independent state-funded schools will drive up standards by giving head teachers more control.
It will be one of the first pieces of legislation passed by the coalition, but critics say it has been rushed and will widen inequalities in schooling.
As well as creating new academies, the law will pave the way for the other major plank of the government's education reforms - "free schools" being set up by parents, teachers and other groups.
Some schools are expected to become academies in September.
About 2,000 have expressed an interest in academy status, the government says, but ministers have not yet revealed how many schools have applied to make the change.
The Anti Academies Alliance, a campaign group, says it is aware of 35 schools that have begun the process to become academies by September.
The first to change will all have been rated "outstanding" by schools inspectors Ofsted, as top-rated schools are being fast-tracked.
Ultimately all good schools - including primaries and special schools - will be able to become academies provided they meet the requirements of a "funding agreement" between themselves and the government.
Academy schools will be:
- Funded by central government rather than through the local council
- Free to set their own curriculum as long as it is "broad and balanced"
- Responsible for their own admissions, but bound by the Admissions Code
- Able to set terms and conditions for teachers and other staff
- Receiving money previously spent on their behalf by councils for services such as those for children with special needs or excluded from school
Free schools will also be set up as academies, in that they will have the same type of agreement or contract with the government.
The legislation removes the current legal requirement for local councils to be consulted when parents or other groups want to set up a school - something some groups had said was a block to their plans.
Councils argue that they need to take an overview of school provision.
Critics - such as Labour and the big teaching unions - say the changes will fragment the state system and favour schools in the most advantaged areas.
They have complained that the Academies Bill was being rushed through parliament.
The government says it is fulfilling a manifesto commitment in passing the law now and that there has been ample time for it to be considered.
The National Union of Teachers says the Bill is an "attack on the very existence of democratically accountable, free state comprehensive education" and that more time for debate should have been allowed.
It is pushing for an amendment to remove a clause in the Bill which allows consultation with parents to take place after a school has been given the green light to convert to an academy.
As the bill went through the Lords, the government added an amendment requiring schools to consult "appropriate groups" if they want to become academies, but it did not specify councils.
Clauses have also been added enshrining the equal rights of pupils with special educational needs and requiring academies to submit to requests under the Freedom of Information Act.
Lib Dem backing
The Liberal Democrats are expected to support the Bill, although party deputy leader Simon Hughes said last week that they would not have supported it if it were not part of the coalition agreement.
And one Lib Dem MP, Mike Hancock, representing Portsmouth South, opposed the Bill at its second reading.
Under the previous government and the then prime minister, Tony Blair, academies were seen as a vehicle for improving education in disadvantaged areas.
They had sponsors who invested up to £2 million, often replaced failing schools and usually came with state-of-the-art buildings.
Education Secretary Michael Gove has praised the ideas and says he want all schools to be free to innovate.
England is the only part of the UK with this type of school.